Magic Mirror

So there are three girls: an ugly redhead, a fat brunette, and a dumb blonde.
The three girls are at a historical inn. They stop to take a tour. The onnkeeper showed them  a mirror. He said  that if you tell a lie in front of it, you disappear.
The ugly redhead goes up to the mirror and says "I think I'm pretty" and POOF! She disappears.
Then the fat brunette goes up to the mirror and says "I think I'm slim" and POOF! She was gone too.
Then the dumb blonde goes up to the mirror and says "I think" and POOF! She was gone.